/* body主体页面占比 */
.body_ {
    background-color: #F5F7F9;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 200vh;
    overflow-y: auto; /* 启用垂直滚动条 */
  }
  
  .centered {
    background-color: white;
    width: 39vw;
    height: 200vh;
  }

  .set_back_to{
    margin-right: 150px;
  }

  .change{
    margin-right: 50px;
  }
  
 